Linear alkylbenzenes (LAB) are compounds that have significant commercial importance. Linear alkylbenzene sulfonate (LAS) compounds made by sulfonation of linear alkylbenzene are used in the manufacture of detergents and other products. Because linear alkylbenzenes are more easily biodegradable than branched alkylbenzenes, linear alkylbenzenes have essentially replaced branched alkylbenzenes in detergents and other products. In particular, linear alkylbenzenes with long alkyl chains, such as chains having about 10 to about 14 carbons, are commonly used. However, linear alkylbenzenes with longer chains and with shorter chains also are commercially important.
Linear alkylbenzenes often are made by alkylation of benzene with olefins. Positional isomers, such as 2-phenyl, 3-phenyl, 4-phenyl, 5-phenyl, and the like, result from this alkylation of benzene with long chain olefins. The distribution of the phenyl along the alkyl chain produces different products.
Historically, linear alkylbenzenes have been manufactured commercially using Friedel-Crafts condensation employing catalysts such as aluminum chloride, or by using strong acid catalysts such as hydrogen fluoride, for example, to alkylate benzene with olefins. Currently, about two thirds of the LAB used for detergent is manufactured using the HF process. However, hydrogen fluoride is hazardous and corrosive, and its use in industrial processes requires a variety of environmental controls.
There has been significant effort in developing alternatives to the HF alkylation process, particularly in the area of motor fuels alkylation. The formulation of detergent products has been built around a particular isomeric distribution of phenyl alkanes produced by HF alkylation. Therefore, it would be desirable to produce a product having a distribution of phenyl alkanes similar to that of HF alkylation and within the commercial range specified based on that distribution.
There exists a need for additional methods for making linear alkylaromatics.